The anti-tank ditch (Panzerabwehrgraben) surrounds the east and northern sides of the Hedgehog. The eastern side is actually part of the anti-invasion defences, dug in 1941, to give depth to the beach defences although non of the obstacle crossing trials were carried out on this section of ditch. The spur that runs of this ditch, protecting the northern face of the Hedgehog was dug in 1943 as part of Exercise Kruschen. Film archive shows it to be dug to the ‘V’ shaped profile, as represented in German Field Engineering manuals. The German manuals show the spoil heaped on the side of the defending lines; intriguingly there is no evidence of any spoil on the ditch dug in 1943. The Germans usually faced and reinforced their anti-tank ditches with logs, steel stakes and wire etc., but there is no evidence on the ground, or in images taken of the exercise, that would indicate this was done. Erosion, mainly by Red Deer, makes it difficult to assess the dimensions of the Kruschen anti-tank ditch but they are approximately 14 ft wide and 8 ft deep in the best preserved sections. In the places where the main armoured fighting vehicle activity took place ditch is now up to 20 ft plus wide and as shallow as 4 ft.
Left: The Kruschen Anti-tank ditch shows
up clearly in this 1945 aerial photo.
Right: Part of the ditch as it is today. This is
one of the sections where the main
armoured fighting vehicle activity took place
Allied Intelligence had the following to say on anti-tank ditches in front of or around defended localities:
“Such ditches are usually 9 to 12 ft wide and possibly about 8 ft deep. On sandy beaches the ditch is generally revetted or lined with concrete or brick.”
It was noted that for strongpoints containing RDF or other wireless installations, there was often an all round ditch with usually a thin belt of wire some 10 to 20 yards in front of the ditch, and a thicker belt some 50 yards behind it.
Intelligence noted that anti-tank ditches were seldom combined with other major obstacles, indicating that the Kruschen obstacle consisting of wire-mines-ditch-mines-wire was constructed to represent the strongest of obstacles that assault teams would have to deal with.
Right: German anti-tank ditch being constructed as part of the
Atlantic Wall. Note the 'V' profile and the drag line in the background.
Brigadier Wales notes the use of Escarpments as one of the obstacles enclosing the Hedgehog. The 1943 German Manual on Field Works shows a tank obstacle created by cutting a bank into a steep slope (Panzerhindernis). The idea was to improve a natural obstacle, saving much time and labour. The spoil was usually placed on the top of the bank or used to fill dead ground in front of the bank. The Kruschen escarpment is up to 5 ft high in places.
It is interesting to note the actual 1941 anti-tank ditch has one side escarped in order to enhance the obstacle. British Field Engineering manuals also illustrate the escarpment as an anti-tank obstacle.
Above: Left - Panzerhindernis as shown in German Field Engineering Manuals. Right - the Kruschen Escarpment
Allied Intelligence noted that minefields were sited around the perimeters of defended localities in continuous belts, each belt usually in 3 to 8 rows, giving a depth between 15 to 40 yards. Minefields were usually surrounded by a thin belt of wire. Given that the maximum length of the “Snakes” used in Kruschen was 400 ft, which had to clear an obstacle consisting of two belts of wire and minefields, one either side of the anti-tank ditch, the Kruschen minefields would not have been very deep.
German barbed wire obstacles (Koppelzaune) where more or less identical to those used by the British – i.e. single and double apron fences or single, double and triple Dannert coil fences. They were supported by screw pickets or angle iron pickets. Allied Intelligence suggested strongpoints were surrounded by two or three belts of wire, the distance between the belts depending on the topography and could vary between 30 to 200 yards. The depth of each individual belt varied between 4 to 20 ft. The distance between the outer edge of the wire perimeter and the nearest pillbox or firing post was not less than 30 yards. Individual posts within a strongpoint were often separated by wire. The main wire obstacle of a defended locality was often associated with anti-personnel mines. Film archive shows a High Wire fence used in Kruschen (i.e. four coils of Dannert wire with a single apron on each side).